Types of Anchors: PROS & CONS

Drill and EpoxyEpoxy anchoring has traditionally been the most popular with general contractors and installers because of its lower cost and ease of installation. Epoxy anchors are drilled and installed post pour of the concrete slab, so the margin of error for placement is drastically reduced. The potential issue with drill and epoxy is

improper hole preparation before installation of the epoxy. If not installed and cured properly, then the epoxy will no longer maintain the required load value to ensure structural integrity of the anchor. Another concern with epoxy anchors is installing

into post tensioned slabs. If the tendon (cable) locations are not clearly marked then drilling could be an issue. Read “Top 5

Epoxy Anchoring Mistakes” for further information.

Cast-in-PlaceCast-in-place anchor bolts are quickly becoming a more

commonly used fastener. With newer multi-residential wood frame structures being constructed on podium concrete slabs

using post tension cables drill and epoxy is not a favorable option because of the potential of drilling and cutting into a tension

cable. Cast-in-place anchors are a good solution for most projects. However, placing anchors can be difficult to accurately position before the casting of concrete. The margin of error is small, so post pour issues can cause many headaches. It’s not

uncommon to miss wall locations which cause project delays. If missed, engineers and general contractors have to design an

alternative solution that meets the required load values.

Embed PlatesEmbed plates are another option that can provide tolerance with

anchorage. However, the prep work to fabricate, plan, and the labor to layout embed plates is costly. For this reason, some general

contractors tend to shy away from using embed plates if possible. The embed plates will be placed during the casting of concrete.

Then, a coupling nut or threaded rod is welded to the plate. It is the placement of welding the threaded rod that gives some tolerance

since the plate provides a larger surface area. But, it is possible embed plate locations are missed, get bumped out of place during the concrete pour, or don’t even make it into the forms prior to the

concrete being poured. These field fixes are not easily dealt with and can delay construction for days, again waiting for redesigned

anchors and fabrication.

Anchorage to Steel Beam

Anchoring to steel beams is common among buildings with large lobbies or interior club houses.

A misplaced steel anchor on a steel frame can be easily moved or replaced by means of grinding off

welds, removing bolts, etc, and relocating the anchor to the correct location. This is an

advantage of welding anchors to steel beams. However, welding has to be completed before the wall sill plates are installed to reduce the risk of a

fire.

The bottom line is anchors are vital to the success of your project timeline and

structural integrity of buildings. Start off on the right path with anchor design and the

entire job will go smoother.